Treating vitamin D insufficiency and deficiency with 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3

ABSTRACT

Methods and compositions for treating 25-hydroxyvitamin D insufficiency and deficiency in a patient are described herein. The method includes orally administering to the patient a delayed, sustained release formulation including a first ingredient selected from the group consisting of 25-hydroxyvitamin D 2 , 25-hydroxyvitamin D 3 , or a combination of 25-hydroxyvitamin D 2  and 25-hydroxyvitamin D 3 , or it includes gradually administering to the patient a sterile intravenous formulation including a first ingredient selected from the group consisting of 25-hydroxyvitamin D 2 , 25-hydroxyvitamin D 3 , or a combination of 25-hydroxyvitamin D 2  and 25-hydroxyvitamin D 3 .

CROSS REFERENCE TO RELATED APPLICATION

The benefit under 35 U.S.C. 119(e) of U.S. Provisional PatentApplication Ser. No. 60/764,665 filed Feb. 3, 2006, is hereby claimed.

The Vitamin D metabolites known as 25-hydroxyvitamin D₂ and25-hydroxyvitamin D₃ (collectively referred to as “25-hydroxyvitamin D”)are fat-soluble steroid prohormones to Vitamin D hormones thatcontribute to the maintenance of normal levels of calcium and phosphorusin the bloodstream. The prohormone 25-hydroxyvitamin D₂ is produced fromVitamin D₂ (ergocalciferol) and 25-hydroxyvitamin D₃ is produced fromVitamin D₃ (cholecalciferol) primarily by one or more enzymes located inthe liver. The two prohormones also can be produced outside of the liverfrom Vitamin D₂ and Vitamin D₃ (collectively referred to as “Vitamin D”)in certain cells, such as enterocytes, which contain enzymes identicalor similar to those found in the liver.

The prohormones are further metabolized in the kidneys into potenthormones. The prohormone 25-hydroxyvitamin D₂ is metabolized into ahormone known as 1α,25-dihydroxyvitamin D₃; likewise, 25-hydroxyvitaminD₃ is metabolized into 1α,25-dihydroxyvitamin D₃ (calcitriol).Production of these hormones from the prohormones also can occur outsideof the kidney in cells which contain the required enzyme(s).

The Vitamin D hormones have essential roles in human health which aremediated by intracellular Vitamin D receptors (VDR). In particular, theVitamin D hormones regulate blood calcium levels by controlling theabsorption of dietary calcium by the small intestine and thereabsorption of calcium by the kidneys. Excessive hormone levels,whether transient or prolonged, can lead to abnormally elevated urinecalcium (hypercalciuria), blood calcium (hypercalcemia) and bloodphosphorus (hyperphosphatemia). The Vitamin D hormones also participatein the regulation of cellular differentiation and growth, PTH secretionby the parathyroid glands, and normal bone formation and metabolism.Further, Vitamin D hormones are required for the normal functioning ofthe musculoskeletal, immune and renin-angiotensin systems. Numerousother roles for Vitamin D hormones are being postulated and elucidated,based on the documented presence of intracellular VDR in nearly everyhuman tissue.

The actions of Vitamin D hormones on specific tissues depend on thedegree to which they bind to (or occupy) the intracellular VDR in thosetissues. The prohormones 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃have essentially identical affinities for the VDR which are estimated tobe at least 100-fold lower than those of the Vitamin D hormones. As aconsequence, physiological concentrations of 25-hydroxyvitamin D₂ and25-hydroxyvitamin D₃ have little, if any, biological actions withoutprior metabolism to Vitamin D hormones. However, supraphysiologic levelsof 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃, in the range of 10 to1,000 fold higher than normal, can sufficiently occupy the VDR to exertactions like the Vitamin D hormones.

Surges in blood or intracellular prohormone concentrations can promoteexcessive extrarenal hormone production, leading to local adverseeffects on calcium and phosphorus metabolism. They also can inhibithepatic prohormone production from Vitamin D, and promote catabolism ofboth Vitamin D and 25-hydroxyvitamin D in the kidney and/or othertissues. Blood levels of both the prohormones and the Vitamin D hormonesare normally constant through the day, given a sustained, adequatesupply of Vitamin D from sunlight exposure or an unsupplemented diet.Blood levels of 25-hydroxyvitamin D, however, can increase markedlyafter administration of currently available Vitamin D supplements,especially at doses which greatly exceed the minimum amounts required toprevent Vitamin D deficiency rickets or osteomalacia. Prohormone bloodlevels can also increase markedly after rapid intravenous administrationof 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃.

Production of 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃ declineswhen Vitamin D is in short supply, as in conditions such as Vitamin Dinsufficiency or Vitamin D deficiency (alternatively, hypovitaminosisD). Low production of 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃leads to low blood levels of 25-hydroxyvitamin D. Inadequate Vitamin Dsupply often develops in individuals who are infrequently exposed tosunlight without protective sunscreens, have chronically inadequateintakes of Vitamin D, or suffer from conditions that reduce theintestinal absorption of fat soluble vitamins (such as Vitamin D). Ithas recently been reported that most individuals living in northernlatitudes have inadequate Vitamin D supply. Left untreated, inadequateVitamin D supply can cause serious bone disorders, including rickets andosteomalacia, and may contribute to the development of many otherdisorders including osteoporosis, non-traumatic fractures of the spineand hip, obesity, diabetes, muscle weakness, immune deficiencies,hypertension, psoriasis, and various cancers.

The Institute of Medicine (IOM) of the National Academy of Sciences hasconcluded that an Adequate Intake (AI) of Vitamin D for a healthyindividual ranges from 200 to 600 IU per day, depending on theindividual's age and sex [Standing Committee on the ScientificEvaluation of Dietary Reference Intakes, Dietary reference intakes:calcium, phosphorus, magnesium, vitamin D, and fluoride. Washington,D.C.: National Academy Press (1997)], incorporated by reference. The AIfor Vitamin D was defined primarily on the basis of a serum25-hydroxyvitamin D level sufficient to prevent Vitamin D deficiencyrickets or osteomalacia (or >11 ng/mL). The IOM also established aTolerable Upper Intake Level (UL) for Vitamin D of 2,000 IU per day,based on evidence that higher doses are associated with an increasedrisk of hypercalciuria, hypercalcemia and related sequelae, includingcardiac arrhythmias, seizures, and generalized vascular and othersoft-tissue calcification.

Currently available oral Vitamin D supplements are far from ideal forachieving and maintaining optimal blood 25-hydroxyvitamin D levels.These preparations typically contain 400 IU to 5,000 IU of Vitamin D₃ or50,000 IU of Vitamin D₂ and are formulated for quick or immediaterelease in the gastrointestinal tract. When administered at chronicallyhigh doses, as is often required for Vitamin D repletion, these productshave significant and, often, severe limitations which are summarizedbelow.

High doses of immediate release Vitamin D supplements produce markedsurges in blood Vitamin D levels, thereby promoting: (a) storage ofVitamin D in adipose tissue, which is undesirable because stored VitaminD is less available for later conversion to 25-hydroxyvitamin D; (b)catabolism of Vitamin D to metabolites which are less or no longeruseful for boosting blood 25-hydroxyvitamin D levels, via 24-and/or26-hydroxylation; and, (c) excessive intracellular 24-or25-hydroxylation of Vitamin D, which leads to increased risk ofhypercalciuria, hypercalcemia and hyperphosphatemia via mass-actionbinding to the VDR.

High doses of immediate release Vitamin D supplements also producesurges or spikes in blood and intracellular 25-hydroxyvitamin D levels,thereby promoting: (a) transiently excessive renal and extrarenalproduction of Vitamin D hormones, and leading to local aberrations incalcium and phosphorus homeostasis and increased risk of hypercalciuria,hypercalcemia and hyperphosphatemia; (b) catabolism of both Vitamin Dand 25-hydroxyvitamin D by 24-and/or 26-hydroxylation in the kidney andother tissues; (c) down-regulation of hepatic production of Vitamin Dprohormones, unnecessarily impeding the efficient repletion of Vitamin Dinsufficiency or deficiency; and, (d) local aberrations in calcium andphosphorus homeostasis mediated by direct binding to VDR.

Furthermore, high doses of immediate release Vitamin D supplementsproduce supraphysiologic, even pharmacological, concentrations ofVitamin D, e.g., in the lumen of the duodenum, promoting: (a)25-hydroxylation in the enterocytes and local stimulation of intestinalabsorption of calcium and phosphorus, leading to increased risk ofhypercalciuria, hypercalcemia and hyperphosphatemia; and (b) catabolismof Vitamin D by 24-and 26-hydroxylation in the local enterocytes,causing decreased systemic bioavailability.

Vitamin D supplementation above the UL is frequently needed in certainindividuals; however, currently available oral Vitamin D supplements arenot well suited for maintaining blood 25-hydroxyvitamin D levels atoptimal levels given the problems of administering high doses ofimmediate release Vitamin D compounds.

Administration of 25-hydroxyvitamin D₃ in an immediate release oralformulation has been tried as an alternative method of Vitamin Dsupplementation. This approach, which has been subsequently abandoned,caused problems as do the currently used Vitamin D supplements.Specifically, it produced surges or spikes in blood and intracellular25-hydroxyvitamin D levels, thereby promoting (a) competitivedisplacement of Vitamin D hormones from the serum Vitamin D BindingProtein (DBP) and excessive delivery of the displaced hormones totissues containing VDR, and (b) transiently excessive renal andextrarenal production of Vitamin D hormones, which together led to localaberrations in calcium and phosphorus metabolism. In addition, thesesurges in blood 25-hydroxyvitamin D levels promoted catabolism of bothVitamin D and 25-hydroxyvitamin D by 24-and/or 26-hydroxylation in thekidney and other tissues, down-regulation of hepatic production ofVitamin D prohormones, unnecessarily impeding the efficient repletion ofVitamin D insufficiency or deficiency, and, additional local aberrationsin calcium and phosphorus homeostasis mediated by direct binding to VDR.Importantly, immediate release 25-hydroxyvitamin D₃ promoted itsintestinal absorption via a mechanism substantially involving transportto the liver in chylomicrons, rather than bound to the serum DBP.Delivery of 25-hydroxyvitamin D to the liver via chylomicronssignificantly increased the likelihood of its catabolism.

Clearly, an alternative approach to Vitamin D supplementation is neededgiven the problems encountered with both currently available oralVitamin D supplements, and with previously used oral 25-hydroxyvitaminD₃.

SUMMARY OF THE INVENTION

The present invention provides methods for effectively and safelyrestoring blood 25-hydroxyvitamin D levels to optimal levels (definedfor patients as >30 ng/mL 25-hydroxyvitamin D) and maintaining blood25-hydroxyvitamin D levels at such optimal levels. The method includesdosing a subject, an animal or a human patient, orally or intravenouslywith sufficient 25-hydroxyvitamin D₂ or 25-hydroxyvitamin D₃ or anycombination of these two prohormones in a formulation that providesbenefits to the recipient that were heretofore unimagined with currentlyavailable Vitamin D supplements. That is, the present invention provideseffective Vitamin D supplementation that reduces the risk of transientsurges (i.e., supraphysiologic levels) of blood 25-hydroxyvitamin D andrelated side effects.

In an embodiment of the present invention, an amount of25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ is included in acontrolled release formulation and is orally administered daily to ahuman or animal in need of treatment. In another embodiment, an amountof 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ is included in anisotonic sterile formulation suitable for intravenous administration,and is gradually injected thrice weekly into a human or animal in needof treatment. This administration of 25-hydroxyvitamin D₂ and/or25-hydroxyvitamin D₃ significantly: increases the bioavailability of thecontained 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃; decreases theundesirable first pass effects of the contained 25-hydroxyvitaminD₂/25-hydroxyvitamin D₃ on the duodenum; avoids producingsupraphysiologic surges in blood levels of 25-hydroxyvitamin D₂ and/or25-hydroxyvitamin D₃; increases the effectiveness of orally administered25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ in restoring bloodconcentrations of 25-hydroxyvitamin D to optimal levels (defined forpatients as >30 ng/mL 25-hydroxyvitamin D); increases the effectivenessof orally administered 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ inmaintaining blood concentrations of 25-hydroxyvitamin D at such optimallevels; decreases disruptions in Vitamin D metabolism and relatedaberrations in PTH, calcium and phosphorus homeostasis; and, decreasesthe risk of serious side effects associated with Vitamin Dsupplementation, namely Vitamin D toxicity.

In one aspect, the present invention provides a stable controlledrelease composition comprising 25-hydroxyvitamin D₂ and/or25-hydroxyvitamin D₃, which is formulated to allow the 25-hydroxyvitaminD to pass through the stomach, and the duodenum and jejunum of the smallintestine, to the ileum. The composition effectively resistsdisintegration in gastric juice, and avoids substantial release of thecontained 25-hydroxyvitamin D until it reaches the ileum of the smallintestine, thereby minimizing absorption substantially mediated bytransport to the liver in chylomicrons. The disclosed composition isgradually presented to the intralumenal and intracellular aspects of theileum, reducing CYP24-mediated catabolism and provoking a sustainedincrease in the blood levels of 25-hydroxyvitamin D to optimal levelswhich can be maintained.

In another aspect, the invention provides an isotonic sterileformulation suitable for gradual intravenous administration containing25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃, which allows the25-hydroxyvitamin D to completely bypass the gastrointestinal tract,thereby eliminating first pass effects on the duodenum and jejunum, aswell as absorption mediated by transport to the liver in chylomicrons.

The foregoing brief description has outlined, in general, the featuredaspects of the invention and is to serve as an aid to betterunderstanding the more complete detailed description which is to follow.In reference to such, there is to be a clear understanding that thepresent invention is not limited to the method or detail of manufacture,chemical composition, or application of use described herein. Any othervariation of manufacture, chemical composition, use, or applicationshould be considered apparent as an alternative embodiment of thepresent invention. Other advantages and a fuller appreciation of thespecific adaptations, compositional variations and chemical and physicalattributes of this invention will be gained upon examination of thedetailed description.

Also, it is understood that the phraseology and terminology used hereinare for the purpose of description and should not be regarded aslimiting. The use of “including”, “having” and “comprising” andvariations thereof herein is meant to encompass the items listedthereafter and equivalents thereof as well as additional items andequivalents thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for dosing a subject, ananimal or a human patient, in need of Vitamin D supplementation withsufficient 25-hydroxyvitamin D₂, 25-hydroxyvitamin D₃ or any combinationof these two prohormones to effectively and safely restore blood25-hydroxyvitamin D levels to optimal levels (defined for human subjectsand patients as >30 ng/mL 25-hydroxyvitamin D) and to maintain blood25-hydroxyvitamin D levels at such optimal levels.

As used herein, the following definitions may be useful in aiding theskilled practitioner in understanding the invention:

As used herein, the term “substantially constant” with respect to theserum or blood level of 25-hydroxyvitamin D means that the releaseprofile of any formulation administered as detailed hereinbelow shouldnot include transient increases in total serum or blood levels of25-hydroxyvitamin D₃ or 25-hydroxyvitamin D₂ of greater thanapproximately 3 ng/mL after administration of a unit dose.

As used herein, the term “controlled release” and “sustained release”are used interchangeably, and refer to the release of the administered25-hydroxyvitamin D at such a rate that total serum or blood levels of25-hydroxyvitamin D are maintained or elevated above predosing levelsfor an extended period of time, e.g. 4 to 24 hours or even longer.

As used herein, the term “Vitamin D toxicity” is meant to refer to theside effects suffered from excessive administration of 25-hydroxyvitaminD and excessively elevated 25-hydroxyvitamin D blood levels, includingnausea, vomiting, polyuria, hypercalciuria, hypercalcemia andhyperphosphatemia.

“Supraphysiologic” in reference to intralumenal, intracellular and bloodconcentrations of 25-hydroxyvitamin D refers to a combined concentrationof 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃ during a 24-hourpost-dose period which is more than 5 ng/mL greater than the generallystable levels observed over the course of the preceding 24-hour periodby laboratory measurement.

“Vitamin D insufficiency and deficiency” is generally defined as havingserum 25-hydroxyvitamin D levels below 30 ng/mL (National KidneyFoundation guidelines, NKF, Am. J. Kidney Dis. 42:S1-S202 (2003),incorporated herein by reference).

Unless indicated otherwise, “25-hydroxyvitamin D₂/25-hydroxyvitamin D₃”as used herein is intended to encompass 25-hydroxyvitamin D₂,25-hydroxyvitamin D₃, or a combination thereof.

Unless indicated otherwise, “25-hydroxyvitamin D” is intended to referto 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃ collectively. Forexample, an assayed blood level of 25-hydroxyvitamin D will include both25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃, if present.

It also is specifically understood that any numerical value recitedherein includes all values from the lower value to the upper value,i.e., all possible combinations of numerical values between the lowestvalue and the highest value enumerated are to be considered to beexpressly stated in this application. For example, if a concentrationrange or a beneficial effect range is stated as 1% to 50%, it isintended that values such as 2% to 40%, 10% to 30%, or 1% to 3%, etc.,are expressly enumerated in this specification. These are only examplesof what is specifically intended.

The invention includes compositions comprising oral and intravenousformulations of 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ andmethods of administering such formulations to treat 25-hydroxyvitamin Dinsufficiency and deficiency without the potential first pass effects ofthese prohormones on the duodenum and jejunum; withoutsupraphysiological surges in intralumenal, intracellular and bloodlevels of 25-hydroxyvitamin D and their consequences; without causingsubstantially increased catabolism of the administered 25-hydroxyvitaminD; and, without causing serious side effects associated with Vitamin Dsupplementation, namely Vitamin D toxicity.

The controlled release compositions intended for oral administration inaccordance with the present invention are designed to containconcentrations of the 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ of 1 to50 mcg per unit dose, and are prepared in such a manner as to effectcontrolled or substantially constant release of the 25-hydroxyvitaminD₂/25-hydroxyvitamin D₃ into the ileum of the gastrointestinal tract ofhumans or animals over an extended period of time. The compositionsensure a (a) substantially increased absorption of 25-hydroxyvitamin Dvia transport on DBP and decreased absorption via transport inchylomicrons, and (b) maintenance of substantially constant blood levelsof 25-hydroxyvitamin D during the 24-hour post-dosing period. Byproviding a gradual, sustained and direct release of the25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ preferentially to circulatingDBP (rather than to chylomicrons), blood, intralumenal and intracellular25-hydroxyvitamin D concentration spikes, i.e., supraphysiologic levelsand related unwanted catabolism are mitigated or eliminated

The compositions intended for intravenous administration in accordancewith the present invention are designed to contain concentrations of the25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ of 1 to 25 mcg per unit dose,and are prepared in such a manner as to allow gradual injection, over aperiod of 1 to 5 minutes, to effect controlled or substantially constantrelease of the 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ directly to DBPin the blood. The compositions ensure complete bioavailability of theadministered 25-hydroxyvitamin D, complete elimination of first passeffects on the duodenum and jejunum, decreased catabolism of25-hydroxyvitamin D, and maintenance of substantially constant bloodlevels of 25-hydroxyvitamin D during the 24-hour post-dosing period. Byproviding a gradual, sustained and direct release of the25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ over time to circulating DBP,intralumenal, intracellular and even blood 25-hydroxyvitamin Dconcentration spikes, i.e., supraphysiologic levels, are mitigated oreliminated.

The compositions of the present invention comprise highly stablepharmaceutical formulations into which 25-hydroxyvitamin D₂ and/or25-hydroxyvitamin D₃ is incorporated for convenient daily oraladministration. The disclosed compositions produce gradual increases inand then sustained blood levels of 25-hydroxyvitamin D with dualunexpected benefits with continued regular administration over aprolonged period of time of unsurpassed effectiveness in restoring blood25-hydroxyvitamin D to optimal levels, and unsurpassed safety relativeto heretofore known formulations of Vitamin D or 25-hydroxyvitamin D.

The preparation of a controlled, substantially constant release form of25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ suitable for oraladministration can be carried out according to many differenttechniques. For example, the 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃can be dispersed within a matrix, i.e. a unique mixture of ratecontrolling constituents and excipients in carefully selected ratioswithin the matrix, and encased with a coating material. Various coatingtechniques can be utilized to control the rate and/or the site of therelease of the 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ from thepharmaceutical formulation. For example, the dissolution of the coatingmay be triggered by the pH of the surrounding media, and the resultinggradual dissolution of the coating over time exposes the matrix to thefluid of the intestinal environment. After the coating becomespermeable, 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ diffuses from theouter surface of the matrix. When this surface becomes exhausted ordepleted of 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃, the underlyingstores begin to be depleted by diffusion through the disintegratingmatrix to the external solution.

In one aspect, a formulation in accordance with the present inventionprovides 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ within amatrix that releasably binds the ingredients in a controlledsubstantially constant release when exposed to the contents of theileum.

The 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ containing matrixis suitably covered with a coating that is resistant to disintegrationin gastric juices. The coated controlled release formulation of25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ is then administered orally tosubjects, e.g., animals or human subjects and patients. As theformulation travels through the proximal portion of the small intestine,the enteric coating becomes progressively more permeable but, in asuitable embodiment, it provides a persisting structural frameworkaround the 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ containingmatrix. The 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ containingmatrix becomes significantly exposed to intestinal fluids in the ileumthrough the permeable overcoating, and the 25-hydroxyvitaminD₂/25-hydroxyvitamin D₃ is then gradually released by simple diffusionand/or slow disintegration of the matrix.

Once released into the lumen of the ileum, the 25-hydroxyvitaminD₂/25-hydroxyvitamin D₃ is absorbed into the lymphatic system or intothe portal bloodstream where it is bound to and transported by the DBP.The major portion of 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ isabsorbed at a point beyond the duodenum and jejunum. These proximalportions of the small intestine can respond to high intralumenal levelsof 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ and, in the process, cancatabolize significant quantities of the 25-hydroxyvitaminD₂/25-hydroxyvitamin D₃. By substantially delaying 25-hydroxyvitaminD₂/25-hydroxyvitamin D₃ release until the ileum, the pharmaceuticalcomposition described herein virtually eliminates these potential firstpass effects on the proximal intestine, and reduces unwanted catabolism.Significant catabolism of administered Vitamin D prior to its absorptioninto the bloodstream significantly lowers its bioavailability.Elimination of first pass effects reduces the risk of Vitamin Dtoxicity. Substantially delayed release of 25-hydroxyvitamin D (i.e.,beyond the duodenum and jejunum) markedly decreases the amount of25-hydroxyvitamin D that is incorporated and absorbed from the smallintestine via chylomicrons (since chylomicron formation and absorptionoccurs primarily in the jejunum) and correspondingly increases theamount of 25-hydroxyvitamin D that is absorbed directly through theintestinal wall and onto DBP circulating in lymph or portal blood.

In one embodiment of the invention, the controlled release oralformulation of 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ isprepared generally according to the following procedure. A sufficientquantity of 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ iscompletely dissolved in a minimal volume of USP-grade absolute ethanol(or other suitable solvent) and mixed with appropriate amounts and typesof pharmaceutical-grade excipients to form a matrix which is solid orsemi-solid at both room temperature and at the normal temperature of thehuman body. The matrix is completely or almost entirely resistant todigestion in the stomach and upper small intestine, and it graduallydisintegrates in the lower small intestine.

In a suitable formulation, the matrix binds the 25-hydroxyvitamin D₂and/or 25-hydroxyvitamin D₃ and permits a slow, relatively steady, i.e.substantially constant, release of the 25-hydroxyvitaminD₂/25-hydroxyvitamin D₃ over a period of four to eight hours or more, bysimple diffusion and/or gradual disintegration, into the contents of thelumen of the lower small intestine. The formulation further has anenteric coating that partially dissolves in aqueous solutions having apH of about 7.0 to 8.0, or simply dissolves slowly enough thatsignificant release of 25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ isdelayed until after the formulation passes through the duodenum andjejunum.

As discussed above, the means for providing the controlled release of25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ may be selected fromany of the known controlled release delivery systems of an activeingredient over a course of about four or more hours including the waxmatrix system, and the Eudragit RS/RL system (of Rohm Pharma, GmbH,Weiterstadt, Germany).

The wax matrix system provides a lipophilic matrix. The wax matrixsystem may utilize, bees wax, white wax, cachalot wax or similarcompositions. The active ingredient(s) are dispersed in the wax binderwhich slowly disintegrates in intestinal fluids to gradually release theactive ingredient(s). The wax binder that is impregnated with the25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ is loaded intopartially crosslinked soft gelatin capsules. The wax matrix systemdisperses the active ingredient(s) in a wax binder which softens at bodytemperature and slowly disintegrates in intestinal fluids to graduallyrelease the active ingredient(s). The system suitably includes a mixtureof waxes, with the optional addition of oils, to achieve a melting pointwhich is higher than body temperature but lower than the meltingtemperature of gelatin formulations typically used to create the shellsof either soft and hard gelatin capsules or other formulations used tocreate enteric coatings.

Specifically, in one suitable embodiment, the waxes selected for thematrix are melted and thoroughly mixed. The desired quantity of oils areadded at this time, followed by sufficient mixing. The waxy mixture isthen gradually cooled to a temperature just above its melting point. Thedesired amount of 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃,dissolved in ethanol, is uniformly distributed into the molten matrix,and the matrix is loaded into soft gelatin capsules. The filled capsulesare treated for appropriate periods of time with a solution containingan aldehyde, such as acetaldehyde, to partially crosslink the gelatin inthe capsule shell. The gelatin shell becomes increasingly crosslinked,over a period of several weeks and, thereby, more resistant todissolution in the contents of stomach and upper intestine. Whenproperly constructed, this gelatin shell will gradually dissolve afteroral administration and become sufficiently porous (without fullydisintegrating) by the time it reaches the ileum to allow the25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ to diffuse slowly fromthe wax matrix into the contents of the lower small intestine.

Examples of other lipid matrices that may be of value are glycerides,fatty acids and alcohols, and fatty acid esters.

Another suitable controlled-release oral drug delivery system is theEudragit RL/RS system in which the active ingredient, 25-hydroxyvitaminD₂ and/or 25-hydroxyvitamin D₃, is formed into granules having adimension of 25/30 mesh. The granules are then uniformly coated with athin polymeric lacquer which is water insoluble but slowly waterpermeable. The coated granules can be mixed with optional additives suchas antioxidants, stabilizers, binders, lubricants, processing aids andthe like. The mixture may be compacted into a tablet which, prior touse, is hard and dry and can be further coated, or it may be poured intoa capsule. After the tablet or capsule is swallowed and comes intocontact with the aqueous intestinal fluids, the thin lacquer begins toswell and slowly allows permeation by intestinal fluids. As theintestinal fluid slowly permeates the lacquer coating, the contained25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ is slowly released. Bythe time the tablet or capsule has passed through the small intestine,about four to eight hours or more later, the 25-hydroxyvitaminD₂/25-hydroxyvitamin D₃ will have been slowly but completely released.Accordingly, the ingested tablet will release a stream of25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ as well as any otheractive ingredient.

The Eudragit system is comprised of high permeability lacquers (RL) andlow permeability lacquers (RS). RS is a water insoluble film formerbased on neutral swellable methacrylic acids esters with a smallproportion of trimethylammonioethyl methacrylate chlorides, the molarratio of the quaternary ammonium groups to the neural ester group isabout 1:40. RL is also a water insoluble swellable film former based onneutral methacrylic acid esters with a small portion oftrimethylammonioethyl methacrylate chloride, the molar ratio ofquaternary ammonium groups to neutral ester groups is about 1:20. Thepermeability of the coating and thus the time course of drug release canbe titrated by varying the proportion of RS to RL coating material. Forfurther details of the Eudragit RL/RS system, reference is made totechnical publications available from Rohm Tech, Inc. 195 Canal Street,Maiden, Mass., 02146. See also, K. Lehmann, D. Dreher “Coating oftablets and small particles with acrylic resins by fluid bedtechnology”, Int. J. Pharm. Tech. & Prod. Mfr. 2(r), 31-43 (1981),incorporated herein by reference.

Other examples of insoluble polymers include polyvinyl esters, polyvinylacetals, polyacrylic acid esters, butadiene styrene copolymers and thelike,

Once the coated granules are either formed into a tablet or put into acapsule, the tablet or capsule is coated with an enteric-coatingmaterial which dissolves at a pH of 7.0 to 8.0. One such pH dependententeric-coating material is Eudragit L/S which dissolves in intestinalfluid but not in the gastric juices. Other enteric-coating materials maybe used such as cellulose acetate phthalate (CAP) which is resistant todissolution by gastric juices but readily disintegrates due to thehydrolytic effect of the intestinal esterases.

The particular choice of enteric-coating material and controlled releasecoating material must provide a controlled and substantially constantrelease over a period of 4 to 8 hours or more so that release is delayeduntil the formulation reaches the ileum. Moreover, the controlledrelease composition in accordance with the present invention, whenadministered once a day, suitably provides substantially constantintralumenal, intracellular and blood 25-hydroxyvitamin D levelscompared to an equal dose of an immediate release composition of25-hydroxyvitamin D₂/25-hydroxyvitamin D₃ administered once a day

In another embodiment of the invention, sterile, isotonic formulationsof 25-hydroxyvitamin D₂, 25-hydroxyvitamin D₃ or combinations thereofmay be prepared which are suitable for gradual intravenousadministration. Such formulations are prepared by dissolving25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ in absolute ethanol,propylene glycol or other suitable solvents, and combining the resultingsolutions with surfactants, salts and preservatives in appropriatevolumes of water for injection. Such formulations can be administeredslowly from syringes via heparin locks or by addition to larger volumesof sterile solutions (e.g., saline solution) being steadily infused overtime.

The dosage forms may also contain adjuvants, such as preserving orstabilizing adjuvants. They may also contain other therapeuticallyvaluable substances or may contain more than one of the compoundsspecified herein and in the claims in admixture.

Advantageously, 25-hydroxyvitamin D₂, 25-hydroxyvitamin D₃ orcombinations thereof together with other therapeutic agents can beorally or intravenously administered in accordance with the abovedescribed embodiments in dosage amounts of from 1 to 100 mcg per day,with the preferred dosage amounts of from 5 to 50 mcg per day. If thecompounds of the present invention are administered in combination withother therapeutic agents, the proportions of each of the compounds inthe combination being administered will be dependent on the particulardisease state being addressed. For example, one may choose to orallyadminister 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ with one ormore calcium salts (intended as a calcium supplement or dietaryphosphate binder), bisphosphonates, calcimimetics, nicotinic acid, iron,phosphate binders, cholecalciferol, ergocalciferol, active Vitamin Dsterols, glycemic and hypertension control agents, and variousantineoplastic agents. In addition, one may choose to intravenouslyadminister 25-hydroxyvitamin D₂ and/or 25-hydroxyvitamin D₃ withcholecalciferol, ergocalciferol, active Vitamin D sterols, glycemic andhypertension control agents, and various antineoplastic agents. Inpractice, higher doses of the compounds of the present invention areused where therapeutic treatment of a disease state is the desired end,while the lower doses are generally used for prophylactic purposes, itbeing understood that the specific dosage administered in any given casewill be adjusted in accordance with the specific compounds beingadministered, the disease to be treated, the condition of the subjectand the other relevant medical facts that may modify the activity of thedrug or the response of the subject, as is well known by those skilledin the art.

The inclusion of a combination of 25-hydroxyvitamin D₃ and25-hydroxyvitamin D₂ in the described delivery systems allows theresulting formulations to be useful in supporting both the Vitamin D₃and Vitamin D₂ endocrine systems. Currently available oral Vitamin Dsupplements and the previously marketed oral formulation of25-hydroxyvitamin D₃ have supported just one or the other system.

The present invention is further explained by the following exampleswhich should not be construed by way of limiting the scope of thepresent invention.

EXAMPLE 1

One Embodiment of a Controlled Release Formulation for OralAdministration

Purified yellow beeswax and fractionated coconut oil are combined in aratio of 1:1 and heated with continuous mixing to 75 degrees Celsiusuntil a uniform mixture is obtained. The wax mixture is continuouslyhomogenized while cooled to approximately 45 degrees Celsius.25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃, in a ratio of 1:1, aredissolved in absolute ethanol and the ethanolic solution is added, withcontinuous homogenization, to the molten wax mixture. The amount ofethanol added is in the range of 1 to 2 v/v %. Mixing is continued untilthe mixture is uniform. The uniform mixture is loaded into soft gelatincapsules. The capsules are immediately rinsed to remove any processinglubricant(s) and briefly immersed in an aqueous solution of acetaldehydein order to crosslink the gelatin shell. The concentration of theacetaldehyde solution and the immersion time is selected to achievecrosslinking to the desired degree, as determined by near-infraredspectrophotometry. The finished capsules are washed, dried and packaged.

EXAMPLE 2

One Embodiment of a Formulation for Gradual Intravenous Administration

TWEEN Polysorbate 20 is warmed to approximately 50 to 60° F. (10 to 16°C.), and 25-hydroxyvitamin D₃, dissolved in a minimal volume of absoluteethanol, is added with continuous stirring. The resulting uniformsolution of 25-hydroxyvitamin D₃, absolute ethanol and TWEEN Polysorbate20 is transferred to a suitable volume of water for injection, which hasbeen thoroughly sparged with nitrogen to remove all dissolved oxygen.Sodium chloride, sodium ascorbate, sodium phosphate (dibasic andmonobasic), and disodium edetate are added, followed by sufficientstirring under a protective nitrogen atmosphere, to produce an isotonichomogeneous mixture containing, per 2 mL unit volume: 20 mcg of25-hydroxyvitamin D₃; <0.01% absolute ethanol; 0.40% (w/v) TWEENPolysorbate 20; 0.15% (w/v) sodium chloride; 1.00% (w/v) sodiumascorbate; 0.75% (w/v) sodium phosphate dibasic anhydrous; 0.18% (w/v)sodium phosphate monobasic monohydrate; and, 0.11% (w/v) disodiumedetate. This mixture is sterilized by filtration and filled, withsuitable protection from oxygen contamination, into amber glass ampuleshaving an oxygen headspace of less than 1%.

EXAMPLE 3

Pharmacokinetics Testing in Dogs

Twenty male beagle dogs are divided randomly into two comparable groupsand receive no supplemental Vitamin D for the next 30 days. At the endof this time, each dog in Group #1 receives a single soft gelatincapsule containing 25 mcg of 25-hydroxyvitamin D₂ prepared in acontrolled release formulation similar to the one disclosed inExample 1. Each dog in the other group (Group #2) receives a singleimmediate-release soft gelatin capsule containing 25 mcg of25-hydroxyvitamin D₂ dissolved in medium chain triglyceride oil. Alldogs have received no food for at least 8 hours prior to dosing. Bloodis drawn from each dog at 0, 0.5, 1, 1.5, 2, 3, 4, 6, 9, 15, 24, 36, and72 hours after dose administration. The collected blood is analyzed forthe contained levels of 25-hydroxyvitamin D, and the data are analyzedby treatment group. Dogs in Group #1 show a slower rise and a lowermaximum (C_(max)) in mean blood levels of 25-hydroxyvitamin D than dogsin Group #2. However, dogs in Group #1 show a more prolonged elevationof mean blood levels of 25-hydroxyvitamin D₂ relative to dogs in Group#2, despite the fact that the C_(max) recorded in Group #1 is lower. Themean area under the curve (AUC), corrected for predose background levels(recorded at t=0), is substantially greater for Group #1 for25-hydroxyvitamin D. These procedures demonstrate that administration of25-hydroxyvitamin D₂ in the formulation described in this invention todogs results in blood levels of 25-hydroxyvitamin D which rise much moregradually and remain more stable than after dosing with the same amountof 25-hydroxyvitamin D₂ formulated for immediate release (in mediumchain triglyceride oil). The greater AUC calculated for blood levels of25-hydroxyvitamin D in Group #1 demonstrates that the bioavailability of25-hydroxyvitamin D₂ formulated as described herein is markedlyimproved.

EXAMPLE 4

Pharmacokinetics Testing in Healthy Normal Volunteers

Sixteen healthy non-obese adults, aged 18 to 24 years, participate in an11-week pharmacokinetic study in which they receive successively, and ina double-blinded fashion, two formulations of 25-hydroxyvitamin D₂. Oneof the formulations (Formulation #1) is a soft gelatin capsulecontaining 100 mcg of 25-hydroxyvitamin D₂ prepared in a controlledrelease formulation similar to the one disclosed in Example 1. The otherformulation (Formulation #2) is an immediate-release soft gelatincapsule of identical appearance containing 100 mcg of 25-hydroxyvitaminD₂ dissolved in medium chain triglyceride oil. For 60 days prior tostudy start and continuing through study termination, the subjectsabstain from taking other Vitamin D supplements. On Days 1, 3 and 5 ofthe study, all subjects provide fasting morning blood samples toestablish pretreatment baseline values. On the morning of Day 8, thesubjects provide an additional fasting blood sample (t=0), are randomlyassigned to one of two treatment groups. Both groups are dosed with asingle test capsule prior to eating breakfast: one group receives acapsule of Formulation #1 and the other group receives a capsule ofFormulation #2. Blood is drawn from each subject at 0.5, 1, 1.5, 2, 3,4, 6, 8, 10, 12, 15, 24, 36, 48, 72 and 108 hours after doseadministration. On the morning of Day 70, the subjects provideadditional fasting morning blood samples (t=0) and are dosed with asingle capsule of the other test formulation prior to eating breakfast.Blood is again drawn from each subject at 0.5, 1, 1.5, 2, 3, 4, 6, 8,10, 12, 15, 24, 36, 48, 72 and 108 hours after dose administration. Allcollected blood is analyzed for the contained levels of25-hydroxyvitamin D, and the data are analyzed by treatment formulationafter correction for baseline content. Formulation #1 is found toproduce a slower rise and a lower C_(max) in mean blood levels of25-hydroxyvitamin D than Formulation #2. However, Formulation #1 alsoproduces a more prolonged elevation of mean blood levels of25-hydroxyvitamin D₂ relative to Formulation #2, despite the fact thatthe recorded C_(max) is lower. The mean AUC is substantially greaterafter administration of Formulation #1 for 25-hydroxyvitamin D. Theseprocedures demonstrate that administration of 25-hydroxyvitamin D₂ inthe formulation described in this invention to healthy human adultsresults in blood levels of 25-hydroxyvitamin D which rise much moregradually and remain more stable than after dosing with the same amountof 25-hydroxyvitamin D₂ formulated for immediate release (in mediumchain triglyceride oil). The greater AUC calculated for blood levels of25-hydroxyvitamin D after dosing with Formulation #1 demonstrates thatthe bioavailability of 25-hydroxyvitamin D₂ formulated as describedherein is better.

EXAMPLE 5

Efficacy Study in Healthy Adult Male Volunteers With Vitamin DInsufficiency

The effectiveness of three different formulations of Vitamin D inrestoring serum 25-hydroxyvitamin D to optimal levels (>30 ng/mL) isexamined in a 23-day study of healthy non-obese men diagnosed withVitamin D insufficiency. One of the formulations (Formulation #1) is asoft gelatin capsule containing 30 mcg of 25-hydroxyvitamin D₃ preparedas illustrated in this invention. The second formulation (Formulation#2) is an immediate-release soft gelatin capsule of identical appearancecontaining 50,000 IU of ergocalciferol dissolved in medium chaintriglyceride oil. The third formulation (Formulation #3) is animmediate-release soft gelatin capsule, also of identical appearance,containing 50,000 IU of cholecalciferol dissolved in medium chaintriglyceride oil. A total of 100 healthy Caucasian and African-Americanmen participate in this study, all of whom are aged 30 to 45 years andhave serum 25-hydroxyvitamin D levels between 15 and 29 ng/mL(inclusive). All subjects abstain from taking other Vitamin Dsupplements for 60 days before study start and continuing through studytermination, and from significant sun exposure. On Day 1 and 2 of thestudy, all subjects provide fasting morning blood samples to establishpre-treatment baseline values of serum 25-hydroxyvitamin D. On themorning of Day 3, the subjects provide an additional fasting bloodsample (t=0), are randomly assigned to one of four treatment groups, andare dosed with a single test capsule prior to eating breakfast: thesubjects in Group #1 each receive a single capsule of Formulation #1,and the subjects in Groups #2 and #3 each receive a single capsule ofFormulation #2 or Formulation #3, respectively. Subjects in Group #4receive a matching placebo capsule. Subjects in Group #1 each receive anadditional capsule of Formulation #1 on the mornings of Days 4 through22 before breakfast, but subjects in Groups #2, #3 and #4 receive noadditional capsules. A fasting morning blood sample is drawn from eachsubject, irrespective of treatment group, on Days 4, 5, 6, 10, 17 and 23(or 1, 2, 3, 7, 14 and 20 days after the start of dosing). All collectedblood is analyzed for the contained levels of 25-hydroxyvitamin D, andthe data are analyzed by treatment group after correction for baselinevalues. Subjects in all four treatment groups exhibit mean baselineserum 25-hydroxyvitamin D levels of approximately 16 to 18 ng/mL, basedon analysis of fasting blood samples drawn on Days 1 through 3. Subjectsin Group #4 (control group) show no significant changes in mean serum25-hydroxyvitamin D over the course of the study. Subjects in Group #1show a steadily increasing mean serum 25-hydroxyvitamin D reaching atleast 30 ng/mL by Day 23. In marked contrast, subjects in Group #2exhibit marked increases in mean serum 25-hydroxyvitamin D for the firstfew days post-dosing, reaching a maximum of just above 25 ng/mL, andthen rapidly declining thereafter. By study end, serum 25-hydroxyvitaminD is significantly lower than baseline in Group #2. Subjects in Group #3exhibit continuing increases in mean serum 25-hydroxyvitamin D throughthe first 2 weeks after dosing with gradual, but progressive, decreasesoccurring thereafter. By study end, mean serum 25-hydroxyvitamin D isbelow 30 ng/mL, being only approximately 11 ng/mL higher thanpre-treatment baseline. The data from this study demonstrate thatadministration of 600 mcg of 25-hydroxyvitamin D₃, formulated asdescribed herein and administered at a dose of 30 mcg per day for 20days, is substantially more effective in restoring low serum levels of25-hydroxyvitamin D to optimal levels than immediate-releaseformulations of 50,000 IU of either ergocalciferol or cholecalciferoladministered in single doses, as currently recommended by the NKF andother leading experts on oral Vitamin D replacement therapy.

EXAMPLE 6

Efficacy and Safety Study in End-Stage Renal Disease Patients ExhibitingVitamin D Deficiency

The efficacy and safety of intravenous 25-hydroxyvitamin D₃ in restoringserum 25-hydroxyvitamin D to optimal levels (>30 ng/mL) are examined ina 3-month study of patients with end-stage renal disease (ESRD)requiring regular hemodialysis and diagnosed with Vitamin Dinsufficiency. The formulation examined in this study is an aqueousisotonic and sterile solution containing 20 mcg of 25-hydroxyvitamin D₃similar to the one disclosed in Example 2. A total of 50 healthyCaucasian, Asian, Hispanic and African-American subjects participate inthis study, all of whom are at least 4-months on regular hemodialysisand have serum 25-hydroxyvitamin D levels below 15 ng/mL. Prior toenrolling, all subjects provide two fasting morning blood samples,separated by at least one week, to establish pre-treatment baselinevalues of serum calcium, plasma intact PTH, and serum 25-hydroxyvitaminD. On the morning of Day 1, the subjects are randomly assigned to one oftwo treatment groups, and they begin thrice weekly dosing with the testpreparation, or with a matching placebo. All dosing occurs duringregularly scheduled hemodialysis sessions and is accomplished by gradualinjection (over a period of 1 to 5 minutes) into the blood exiting fromthe hemodialysis machine. Additional fasting blood samples and 24-hoururine collections are obtained from each subject at quarterly intervalsfor determination of serum calcium, plasma intact PTH and serum25-hydroxyvitamin D. Throughout the study, all subjects adhere to adaily intake of approximately 1,000 to 1,500 mg of elemental calcium(from self-selected diets and calcium supplements, as needed) under theongoing guidance of a dietician. At the conclusion of the study, thelaboratory data are analyzed by treatment group and by test formulationafter appropriate correction for baseline values. Both groups havecomparable mean baseline values for serum 25-hydroxyvitamin D (range:10.7 to 11.9 ng/mL), plasma intact PTH (range: 45.3 to 52.1 pg/mL) andserum calcium (range: 8.72 to 9.31 mg/dL). No significant changes in anyof the laboratory mean values are observed in the placebo (control)group over the course of the study. Subjects in the treatment groupreceiving 25-hydroxyvitamin D₃ exhibit progressively increasing serum25-hydroxyvitamin D levels during the first 3 months of dosing, reachingsteady state levels thereafter. Mean serum calcium increasessignificantly from baseline in the treatment group receiving25-hydroxyvitamin D₃, and is significantly higher than those observed inthe placebo group. Episodes of hypercalcemia, defined as serum calciumabove 9.5 mg/dL, are infrequently observed in both treatment groups.Data from this study demonstrate that the intravenous formulation of25-hydroxyvitamin D₃ is effective at increasing serum 25-hydroxyvitaminD without causing unacceptable side effects related to calcium and PTHmetabolism.

All patents, publications and references cited herein are hereby fullyincorporated by reference. In case of conflict between the presentdisclosure and incorporated patents, publications and references, thepresent disclosure should control.

What is claimed is:
 1. A method of treating 25-hydroxyvitamin Dinsufficiency or deficiency in a patient comprising orally administeringto the patient a sustained release formulation of 25-hydroxyvitamin D₂,25-hydroxyvitamin D₃, or a combination of 25-hydroxyvitamin D₂ and25-hydroxyvitamin D₃.
 2. The method of claim 1, comprising administering1 to 100 mcg per day of the 25-hydroxyvitamin D₂, 25-hydroxyvitamin D₃,or combination of 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃.
 3. Themethod of claim 1, comprising administering an effective amount of theformulation to increase the patient's serum total 25-hydroxyvitamin Dlevel to at least 30 ng/mL.
 4. The method of claim 1, wherein theadministration provides a lower maximum (C_(max)) blood level of25-hydroxyvitamin D compared to an equal dose of an immediate releaseformulation.
 5. The method of claim 4, wherein the administration avoidsa transient supraphysiologic surge of blood 25-hydroxyvitamin D.
 6. Themethod of claim 1, wherein the administration avoids transient increasesin blood levels of 25-hydroxyvitamin D of greater than 3 ng/mL followinga unit dose.
 7. The method of claim 1, wherein the administrationincreases the bioavailability of 25-hydroxyvitamin D₂, 25-hydroxyvitaminD₃, or a combination of 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃,compared to an equal dose of an immediate release formulation.
 8. Themethod of claim 1, wherein the formulation comprises an amount of25-hydroxyvitamin D₂, 25-hydroxyvitamin D₃, or a combination of25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃ in a range of 1 mcg to 50mcg.
 9. The method of claim 1, wherein the formulation comprises the25-hydroxyvitamin D₂, 25-hydroxyvitamin D₃, or a combination of25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃ dispersed within a matrixcomprising a release-controlling constituent.
 10. The method of claim 8,wherein the matrix comprises a wax matrix.
 11. The method of claim 1,wherein the administration is once a day.
 12. The method of claim 1,wherein the administration is of an amount of 25-hydroxyvitamin D₂,25-hydroxyvitamin D₃, or a combination of 25-hydroxyvitamin D₂ and25-hydroxyvitamin D₃ in a range of 1 mcg to 100 mcg per day.
 13. Themethod of claim 12, wherein the administration is of an amount of25-hydroxyvitamin D₂, 25-hydroxyvitamin D₃, or a combination of25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃ in a range of 5 mcg to 50mcg per day.
 14. A method of treating 25-hydroxyvitamin D insufficiencyor deficiency in a patient comprising gradually administering to thepatient a formulation of 25-hydroxyvitamin D₂, 25-hydroxyvitamin D₃, ora combination of 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃ to avoida transient supraphysiologic surge of blood 25-hydroxyvitamin D.